A derecho, the kind of storm that knocked out power to millions in Washington last month, may accompany bad weather forecast for New York City and the rest of the Northeast tomorrow, the U.S. Storm Prediction Center said.

There’s a moderate chance the rare windstorm will develop in an area from Indiana to Massachusetts, the center said on its website. The region is also at risk for severe thunderstorms, hail and possible tornadoes after noon, according to John Hart, a meteorologist at the agency’s Norman, Oklahoma, offices....